What is personal radiation monitoring and why do some people who work with ionising radiation need to wear dosimeters?

Personal radiation monitoring devices or dosimeters (PMDs) are badges that detect various forms of radiation a worker may be exposed to. The dosimeter or badge detects the exposure of a person to x-rays, gamma radiation, neutron and beta particles. Workers are required to wear the dosimeters for periods of up to three months. The accumulated dose from the various types of radiation is measured by the dosimetry service provider and reported to the employer.

The Radiation Control Regulation 2013 imposes responsibilities on employers to record and monitor all occupationally exposed persons in their employ who are involved in the use of ionising radiation for any one of the purposes listed in the Regulation (see below). Employees who are exposed to radiation as part of their occupation must be provided with an appropriate and approved PMD when using radioactive substances and radiation apparatus.

Employees issued with a PMD by their employer are required under the legislation to wear the personal monitoring dosimeters/devices while at work.

Employers must ensure that all occupationally exposed employees using ionising radiation for the purposes listed in the Regulation are issued with a personal monitoring dosimeter. The dosimeter detects and measures an employee's cumulative dose of exposure to radiation. The employer should monitor the accumulated dose to ensure that the employee's work practices result in exposures well below 20 millisieverts (mSv) effective dose averaged over five consecutive calendar years or a maximum of 50 mSv in any single year.

Occupationally exposed persons requiring monitoring

A personal monitoring dosimeter must be issued to persons working with the following uses of radiation:

radiotherapy

industrial radiography

nuclear medicine

equine veterinary radiography,

scientific research in laboratories classified as medium or high level laboratories where radioactive substances not contained in a sealed source device are used

An employee's responsibilities

An occupationally exposed person who has been issued with a PMD by their employer must wear the monitor while using ionising radiation in the course of their employment.

An employee may be fined for not wearing the dosimeter when working with ionising radiation.

If an employee is required to wear a lead gown during the course of their duties, the PMD should be worn under the gown.

When a PMD has been issued to an employee, a control PMD must also be provided to measure background radiation received by the wearer. This control PMD must be stored in an area where only background radiation will be measured.

When the defined issuing period has passed, all PMDs including the control must be returned to the service provider for measurement. PMDs that have not been issued, or if issued have not been worn, must also be returned to the service provider.

Recording personal radiation exposure

An employer must ensure that the exposure doses of radiation received are recorded for each employee to whom a personal monitoring dosimeter has been issued. These records must be reviewed at intervals usually not exceeding three months.

The record kept by an employer must contain the following information:

The amount of radiation to which the person has been exposed as measured by the dosimeter. The dose should be recorded in sieverts.

The results of any tests carried out by the employer to determine the amount of radiation to which the employee has been exposed.

current home address or if the person is no longer employed by the employer, the person's last known home address

the date employment commenced and the date the employee ceased employment, if they are no longer employed there

the kind of work performed by the employee

details of the types of ionising radiation to which the employee may have been exposed in the course of their employment, including information about unsealed radioactive substances to which they may have been exposed

details must be provided of any radiation accidents in which the employee has been involved or by which they may have been affected

details of the PMD worn by the employee, which may include the type of monitor, where on the body the monitor was worn and the name of the PMD service provider

the radiation exposure dose results for the employee.

When an employee leaves their place of employment, the employer must provide the following:

A copy of their radiation exposure records. This must include all annual dose records and any subsequent periodic reports received after the employee has ceased employment. It may be necessary to send these to the current address of the former employee.

An additional copy of the radiation exposure records must be provided to the new employer if requested by the employee. These records are required to be given to a new employer so that an assessment can be made of possible future doses that can be received to keep an employee under their annual limit.

An employer must ensure the following warning is included on copies of radiation exposure records provided to an employee. (Records must include the requirements listed above).

These records should be kept safely and permanently and
be given to any future employer employing you as a radiation worker.

An employer who is required to keep records of personal radiation exposure must ensure that an employee's records are available for them to see at a convenient time during normal working hours.

Managing employee dose rates

When a dose report is received from the dosimetry service provider, a review with previous reports should be made. This is to determine if the employee's previous 12-month and five-year dose rates are within the required limits of 20 mSv per year, averaged over a period of five consecutive calendar years.

The employer should make a note of any high dose rates received by employees. The PMD service provider should highlight these high dose rates. If the dose rate exceeds 400 microsieverts (µSv) in any week averaged over the period of monitoring, it is considered that the employee has received a high dose. For incidents where this has occurred, a letter may be required from the Environment Protection Authority (EPA) seeking an explanation from the employer as to why such a dose was received. A change in work practice or role should be considered to manage an employee's annual dose, if a high dose report has been received.

Personal radiation monitoring dosimeter service providers

The EPA must approve all PMDs and their providers used in NSW. A current listing of providers of approved PMDs can be found under radiation monitoring.

The Chair of the EPA may impose conditions on the approval of a PMD.

Under the requirements of Division 2 of the Radiation Control Regulation employers are required to ensure that all monitoring devices that are issued or installed are checked, maintained and calibrated in accordance with the Guideline: Monitoring Devices (PDF 121KB).

More information

For further information, contact the EPA's Hazardous Materials, Chemicals and Radiation Section on (02) 9995 5959 or 131 555.